Mask and method of manufacturing the same

A mask, comprising:

• a first mask that includes a first long side that extends in a first direction and a first short side that extends in a second direction that crosses the first direction, wherein the first long side is longer than the first short side, wherein the first mask includes a first edge portion, a first center portion, and a first welded portion, that are sequentially arranged in the first direction;
• and
• a second mask that includes a second long side that extends in the first direction and a second short side that extends in the second direction, wherein the second long side is longer than the second short side, wherein the second mask includes a second welded portion, a second center portion, and a second edge portion, that are sequentially arranged in the first direction,
• wherein the first welded portion is in contact with the second welded portion,
• wherein the first welded portion includes a first concave-convex portion that has an oscillating shape in a plane, the second welded portion includes a second concave-convex portion that has an oscillating shape in a plane, and the first concave-convex portion is engaged with the second concave-convex portion.